JP7094184B2 - Monitoring device - Google Patents

Description

The present invention relates to a device for monitoring the movement of a monitored object such as a person.

Conventionally, as a device of this type, for example, those found in Patent Documents 1 and 2 are known. The devices found in these Patent Documents 1 and 2 measure the distance to a person as a monitored object on the bed by using a non-contact type distance measuring device that transmits and receives measurement signals such as infrared rays, and the distance thereof is measured. The movement of a person on the bed is detected based on the measured distance.

Japanese Patent Application Laid-Open No. 2003-290154 Japanese Unexamined Patent Publication No. 2012-30042

The device described in Patent Document 1 is capable of detecting the displacement of the chest due to human breathing. However, the displacement of the chest associated with human breathing is generally a minute displacement. Then, in order to be able to detect such a minute displacement by using the distance measuring device, a distance measuring device capable of performing distance measurement with high resolution is required. As a result, an expensive distance measuring device is required, and the monitoring device tends to be expensive. In addition, due to the influence of disturbance noise, it tends to be difficult to measure minute displacements with high reliability.

The present invention has been made in view of this background, and an object of the present invention is to provide a monitoring device capable of easily detecting minute movements of a monitored object with high reliability.

In order to achieve the above object, the monitoring device of the present invention includes a transmission unit that transmits a measurement signal to an area where a monitoring object exists, and a reception unit that receives a reflection signal of the measurement signal transmitted from the transmission unit. A monitoring device including a distance measuring unit that measures a distance to a measurement point set in the region based on the transmitted measurement signal and the received reflected signal.
At the measurement point, the measured value of the distance at the measurement point by the distance measuring unit changes according to a predetermined movement of the monitored object in the region, and the measured value of the distance is changed in the process of the change. Changes to a value larger than a predetermined amount by a predetermined amount or more than the actual distance, or the amount of change in the measured value of the distance in the process of the change is the actual distance according to the predetermined movement of the monitored object. It is a measurement point set so that the amount of change is larger than the specified amount of change.
It is characterized by including a motion detection unit that detects the occurrence of a predetermined motion of the monitored object based on a change in a measured value of a distance at the measurement point.

Here, according to various experiments and studies of the present inventor, there is a case where the portion corresponding to a certain measurement point of the monitored object is a portion capable of reflecting the measurement signal in a manner in which diffuse reflection of the measurement signal is unlikely to occur. It was confirmed that the distance measurement value at the measurement point of the portion changes with the movement of the portion by a large change amount deviating from the actual distance change amount of the portion.

Therefore, the present invention is configured as described above. According to the present invention, even if the change in the actual distance at the measurement point due to the predetermined movement of the monitored object is minute, the measured value of the distance at the measurement point is larger than the actual distance. Also changes to a large value by a predetermined amount or more, or the change amount of the measured value of the distance becomes a larger change amount by a predetermined amount or more than the change amount of the actual distance accompanying the predetermined movement of the monitored part. Become. Therefore, the motion detection unit can easily detect the occurrence of a predetermined motion of the monitored object based on the change in the measured value of the distance at the measurement point. Therefore, according to the present invention, minute movements of the monitored object can be easily detected with high reliability.

In the present invention, the monitored object may be the chest of a person, and the predetermined movement may be vibration of the chest of the person accompanying the breathing of the person. In this case, the vibration of the person's chest accompanying the person's breathing is a vibration with a relatively small amplitude, but according to the present invention, the measured value of the distance at the measurement point reaches the chest during the person's breathing. It changes to a value larger than a predetermined amount by a predetermined amount or more than the actual distance, or the change amount of the measured value of the distance is a large change by a predetermined amount or more than the change amount of the actual distance of the chest due to human breathing. It changes with the amount. Therefore, the vibration of the chest of the person due to the breathing of the person can be easily detected with high reliability.

Further, in the present invention, the surface portion of the monitored object or the object in contact with the surface portion in the local region including the measurement point in the region is attached to the transmitting portion in accordance with the predetermined movement of the monitored object. It is a reflection object of the measurement signal attached so as to change its posture, and the diffused reflection of the measurement signal is less likely to occur than the surface portion of the monitoring object or an object in contact with the surface portion around the local region. It is preferable to further include a reflective object.

According to this, it is possible to easily set a measurement point at which the measured value of the distance can change as described above. In addition, the "object in contact with the surface portion" of the monitored object means, more specifically, an object in direct or indirect contact with the surface portion so that the movement of the surface portion is transmitted and moves.

The figure which shows schematic about the whole structure of the monitoring apparatus of embodiment of this invention. The block diagram which shows the main part composition of each of the distance measuring device and the external monitoring device provided in the monitoring device of an embodiment. The figure which shows the arrangement structure of the reflection part provided in the monitoring apparatus of embodiment. FIG. 4A is a diagram illustrating a person who measures a distance with a distance measuring device, FIG. 4B is a diagram illustrating a distance image measured by the distance measuring device, and FIG. 4C is a graph illustrating a waveform of a change in a distance measurement value.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4C. With reference to FIG. 1, the monitoring device of the present embodiment is a device for monitoring a predetermined movement of a person P who sleeps on a bed B in a room such as a hospital. In this case, the movement of the monitored object of the person P is, for example, the movement of the chest Pa (displacement of the surface of the chest Pa) accompanying the breathing of the person P. Therefore, in the present embodiment, the chest Pa of the person P corresponds to the monitored object in the present invention. The chest Pa includes not only the front side portion of the body of the person P but also the left and right side surface portions and the back surface portion of the upper part of the body.

The monitoring device of the present embodiment includes a distance measuring device 1 arranged indoors and an external monitoring device 10 arranged at an external nurse station or the like or carried by the nurse or the like. The distance measuring device 1 sets the distance to a plurality of measuring points within a predetermined measurement target area on the front side of the distance measuring device 1 (for example, in the area between two alternate long and short dash lines in FIG. 1) by a TOF method (TOF). : Time Of Flight) is a measurable device.

The distance measuring device 1 is attached to an appropriate place in the room, for example, the ceiling so that the chest Pa of the person P who sleeps on the bed B is included in the measurement target area. The distance measuring device 1 is not limited to the ceiling, and may be attached to, for example, a wall, a bed B, or the like.

Then, the distance measuring device 1 outputs a pulse-modulated optical signal toward each of the plurality of measurement points as shown in FIG. 2 in order to measure the distance by the TOF method (TOF: Time Of Flight). While controlling the operation of the light emitting unit 2 which is possible, the light receiving unit 3 which receives the reflected light signal which is the light signal reflected at each measurement point, and the light emitting unit 2, the light emitting unit 2 toward each measurement point. It includes a measurement processing unit 4 that generates measurement data of the distance to each measurement point based on the phase difference between the output optical signal and the reflected light signal received by the light receiving unit 3 corresponding to the optical signal. ..

In this case, the optical signal is, for example, an optical signal having a wavelength in the infrared region. Further, the light emitting unit 2 is composed of, for example, an LED or the like, the light receiving unit 3 is composed of, for example, a photodiode array or the like, and the measurement processing unit 4 is composed of, for example, an electronic circuit unit including a processor or the like. Further, in the present embodiment, the measurement processing unit 4 can output the entire measurement data of the distances of the plurality of measurement points in the measurement target area as distance image data.

In the present embodiment, the optical signal output from the light emitting unit 2 and the reflected light signal received by the light receiving unit 3 correspond to the measurement signal and the reflected signal in the present invention, respectively, and the light emitting unit 2 and the light receiving unit 3 Corresponds to the transmitting unit and the receiving unit in the present invention, respectively. Further, the measurement processing unit 4 corresponds to the distance measurement unit in the present invention.

The external monitor device 10 can communicate with the distance measuring device 1 by wire or wirelessly, and as shown in FIG. 2, a monitor that executes a monitoring process relating to the movement of the chest Pa of the person P on the bed B. It includes a processing unit 11, a display 12 composed of a liquid crystal display and the like, and a sounding device 13 composed of a speaker, a buzzer and the like. In addition to these, the external monitor device 10 may include an input operation unit such as a keyboard and a touch panel, an alarm lamp, and the like.

The monitoring processing unit 11 is composed of an electronic circuit unit including, for example, a microcomputer, a memory, an interface circuit, and the like. The monitoring processing unit 11 has a function as a motion detection unit in the present invention, and while the person P is sleeping on the bed B, the breathing of the person P is based on the distance image data given from the distance measuring device 1. The process of monitoring the movement (vibration) of the chest Pa accompanying the movement (vibration) is executed. Further, the monitoring processing unit 11 appropriately displays waveform data indicating the movement of the chest Pa due to the breathing of the person P on the display 12, and displays notification information regarding the abnormal occurrence of the movement of the chest Pa, etc. It has a function of controlling the display 12 and the sounding device 13 so that one or both of the sounding devices 13 output the data.

The external monitoring device 10 having the monitoring processing unit 11 may be configured as a dedicated device for the monitoring device, but for example, a personal computer in which a monitoring application is installed, or a mobile phone such as a smartphone or a tablet terminal. It may be a terminal.

It should be noted that a part of the processing function of the measurement processing unit 4 of the distance measuring device 1 (for example, the generation processing of distance image data) is realized as the processing function of the monitoring processing unit 11 instead of the measurement processing unit 4. It is also possible to realize it as a processing function in collaboration with the measurement processing unit 4 and the monitoring processing unit 11. Similarly, a part of the processing function of the monitoring processing unit 11 is realized as a processing function of the measurement processing unit 4 instead of the monitoring processing unit 11, or by cooperation between the measurement processing unit 4 and the monitoring processing unit 11. It can also be realized as a processing function.

As shown in FIG. 3, the monitoring device of the present embodiment further has a plurality of thin-film reflecting portions 21 attached to the comforter C used by the person P who sleeps on the bed B. Each reflective unit 21 corresponds to a reflective object in the present invention, and when an optical signal output from the light emitting unit 2 of the distance measuring device 1 is incident on the surface thereof, the reflective unit 21 does not generate so much diffuse reflection. It is configured to be able to reflect an optical signal (in other words, to be able to reflect an incident optical signal mainly in a direction corresponding to its incident angle). For example, the reflective portion 21 may be formed of a thin-film resin member whose surface is a smooth glossy surface, a screen cloth, or the like.

The plurality of reflective portions 21 are arranged vertically and horizontally on the surface of the flexible sheet member 20 attached by stitching or the like on the surface portion of the quilt C on the head side, and the sheets are arranged by an adhesive or the like. It is fixed to the member 20. In this case, the mounting position of the seat member 20 with respect to the quilt C (and by extension, the position at each reflection portion 21 with respect to the quilt C) is one or more reflection portions with the person P sleeping on the bed B hanging the quilt C. 21 is set to be located immediately above the chest Pa of the person P.

In addition, each reflective portion 21 may be directly attached to the surface portion of the quilt C on the head side. Alternatively, each reflective portion 21 may be incorporated in the cover as a part of the cover of the comforter C.

Supplementally, while the person P is sleeping, all of the plurality of reflective portions 21 are displaced from the upper position of the chest Pa due to the relative movement of the person P with respect to the quilt C, the movement of the quilt by the person P, and the like. In some cases. Therefore, not only the comforter C but also a plurality of reflective portions 21 may be attached to the peripheral portion of the chest Pa of the costume worn by the person P on the upper body.

Next, the operation of the monitoring device of the present embodiment will be described. Here, first, in the present embodiment, the principle of the method for detecting the movement of the chest Pa accompanying the breathing of the person P will be described with reference to FIGS. 4A to 4C.

FIG. 4A shows a situation in which the human PP sits on a chair facing the table TB. In this case, a string hanging the plate PL is hung on the neck of the human PP, and the plate PL is located on the front side of the chest of the human PP. The surface of the plate PL is a smooth reflecting surface capable of reflecting the optical signal like the reflecting portion 21.

Then, FIG. 4B shows a distance image (instantaneous distance image) obtained when the person PP shown in FIG. 4A is experimentally measured from the front side thereof by the distance measuring device 1. In FIG. 4B, the larger the distance measurement value, the darker the image becomes, and the smaller the distance measurement value, the brighter the image becomes white. Further, FIG. 4C shows the waveform of the time-dependent change of the distance measurement value at one measurement point X of the plate PL in the distance image of the human PP.

Here, with the breathing of the human PP, the surface of the chest of the human PP (the surface on the front side of the human PP) is displaced so as to vibrate in the anteroposterior direction, and following this, the surface of the human PP in the anterior-posterior direction. The position of the plate PL (and thus the distance from the distance measuring device 1) is displaced so as to vibrate. Therefore, as shown in FIG. 4C, the waveform of the change with time of the distance measurement value of the measurement point X at the location of the plate PL is a oscillating waveform. Then, in this case, it was confirmed that the vibration amplitude amount (peak to peak amplitude amount) of the distance measurement value deviates to a value significantly larger than the actual amplitude amount.

Specifically, in the above experiment, the distance measurement value at the measurement point X became a minimum value when the human PP inhaled, and the minimum value was about 1700 mm. This distance measurement value is about the same as the distance measurement value to the measurement point of the human PP other than the location of the plate PL.

It should be noted that since diffuse reflection of the incident optical signal generally occurs at the measurement point of the human PP other than the point of the plate PL, the distance measuring device 1 can be used from the measuring point regardless of the direction of the reflecting surface at the measuring point. The reflected light signal may be directly incident on the light receiving unit 3. Therefore, the distance measurement value at the measurement point of the human PP other than the location of the plate PL generally matches the actual distance from the distance measuring device 1 to the human PP. In fact, it was confirmed that the distance measurement values at the measurement points of the human PP other than the location of the plate PL were maintained at almost constant values as shown in FIG. 4B.

On the other hand, the distance measurement value at the measurement point X became a maximum value in a state where the human PP exhaled, and the maximum value was a large value of about 3120 mm. Therefore, the amplitude of the vibration of the distance measurement value at the measurement point X is 1420 mm (= 3120-1700 mm), which is much larger than the actual amplitude. Then, FIG. 4B is a distance image near the time when the distance measurement value at the measurement point X becomes the maximum value. Therefore, in FIG. 4B, the brightness corresponding to the distance measurement value at the plate PL is as bright as the background portion of the human PP.

In FIG. 4C, since the description of the data of the distance measurement value of 2000 mm or more is omitted, the maximum value (maximum value) of the distance pole measurement value on the waveform in the figure is 2000 mm, but it is actually The maximum value was as large as about 3120 mm as described above.

As described above, the following reasons can be considered as the reason why the amplitude of the distance measurement value at the measurement point X at the point of the plate PL becomes a value significantly larger than the actual amplitude. That is, in the above experiment, in the vicinity of the time when the distance measurement value becomes the minimum value (near the time when the human PP inhales), most of the optical signals (reflected light signals) reflected by the plate PL are in the distance measuring device 1. It is considered that the light is directly incident on the light receiving unit 3. Therefore, it is considered that the minimum value of the distance measurement value is about the same as the actual distance to the human PP (≈ distance measurement value at the measurement point of the human PP other than the point of the plate PL). Be done.

On the other hand, in the vicinity of the time when the distance measurement value at the measurement point X becomes the maximum value (near the time when the human PP exhales), the plate PL is slightly behind the time when the distance measurement value becomes the minimum value. In addition to being displaced to, it is probable that the attitude (direction) of the plate PL with respect to the distance measuring device 1 (light emitting unit 2 and light receiving unit 3) has changed. Therefore, in the vicinity of the time when the distance measurement value becomes the maximum value, most of the optical signals (reflected light signals) reflected by the plate PL do not directly enter the light receiving unit 3 of the distance measuring device 1 and other points. It is probable that the light was incident on the light receiving unit 3 of the distance measuring device 1 through the reflection in. Therefore, the maximum value of the distance measurement value becomes a value significantly larger than the actual distance to the human PP, and the amplitude of the distance measurement value becomes significantly larger than the actual amplitude. it is conceivable that.

Further, since the change in the posture of the plate PL accompanying the respiration of the human PP occurs in synchronization with the respiration, it is considered that the distance measurement value at the measurement point X vibrates in synchronization with the respiration of the human. In fact, the period T1 in FIG. 4C is a period during which the human PP breathes slowly, and in the period T1, the vibration cycle of the distance measurement value is long. Further, the period T2 in FIG. 4C is a period during which the human PP breathes quickly, and in the period T2, the vibration cycle of the distance measurement value is shortened.

Supplementally, in the above experiment, when the human PP exhaled, the distance measurement value at the measurement point X became the maximum value of a large value deviating from the actual distance, but the plate accompanying the breathing of the human PP. Depending on how the posture of the PL changes, it is considered that the distance measurement value at the measurement point X may become the maximum value of a large value deviating from the actual distance while the human PP inhales.

From the above, if a reflector such as the plate PL capable of reflecting the optical signal is arranged on the surface of the chest of the human PP in an manner in which diffuse reflection of the optical signal is unlikely to occur, it accompanies the breathing of the human PP. Due to the change in the posture of the reflective object, the distance measurement value at the location of the reflective object vibrates, and the amplitude of the vibration of the distance measurement value becomes a large amplitude that greatly deviates from the actual amplitude, or the distance measurement. It is considered that the maximum value of the value becomes a large value that deviates significantly from the actual distance.

Therefore, by observing the vibration of such a distance measurement value, it is considered possible to grasp the presence or absence of a small displacement of the surface portion of the chest due to the respiration of the human PP, the vibration cycle of the displacement, and the like. This is the principle of the method for detecting the movement of the chest Pa accompanying the breathing of the person P in the present embodiment.

On the premise of the above, the operation of the monitoring device of the present embodiment will be described below. While the person P is sleeping on the bed B, the distance measuring device 1 outputs an optical signal to each measurement point in the measurement target area and receives a reflected light signal at each measurement point in a predetermined processing cycle. Distance measurement is performed by the TOF method. Then, the measurement processing unit 4 of the distance measuring device 1 sequentially transmits the distance image data obtained by the distance measurement to the external monitoring device 10.

On the other hand, in the monitoring processing unit 11 of the external monitoring device 10, the distance measurement value is vibrating from the area on the bed B of the distance image data received from the distance measurement device 1, and the distance measurement value is maximized. The value (or the maximum value within a predetermined time width) is a reference value within a standard distance range predetermined as a standard range of the actual distance from the distance measuring device 1 to the person P (for example, the standard). From the maximum value or the median value of the distance range), a measurement point that deviates from the standard distance range by a predetermined amount or more and a large value is extracted as a measurement point of interest.

Alternatively, the monitoring processing unit 11 of the external monitoring device 10 vibrates the distance measurement value from the region on the bed B of the distance image data received from the distance measurement device 1, and the vibration of the distance measurement value. A measurement point in which the amplitude of is larger than a predetermined amount (amplitude sufficiently larger than the normal amplitude of the displacement of the surface portion of the chest Pa due to the breathing of the person P) is extracted as a measurement point of interest.

Here, in a state where the comforter C is hung on the sleeping person P on the bed B, one or more of the reflection portions 21 usually attached to the comforter C as described above. Is located above the chest Pa of the person P, and the posture of the surface of the reflection portion 21 (the posture relative to the distance measuring device 1) changes with the breathing of the person P.

Therefore, usually, one or more measurement points at the points of one or more reflection units 21 are extracted as attention measurement points by the monitoring processing unit 11.

Then, the monitoring processing unit 11 is, for example, based on the time series of the distance measurement values at each of the extracted measurement points of interest, the time width of the period from the time when the distance measurement value increases to the time when the distance measurement value decreases next (hereinafter, hereafter). The increase / decrease time width) and the time width of the period from the decrease of the distance measurement value to the next increase (hereinafter referred to as the decrease / increase time width) are estimated, and the increase / decrease time width and the increase / decrease time width are estimated. It is determined whether or not each estimated value of the decrease / increase time width deviates from the predetermined reference range as the normal range during normal breathing of the person P.

Then, when any of the increase / decrease time width and the decrease / increase time width deviates from the reference range, the monitoring processing unit 11 detects the measurement point of interest near the time when the deviation occurs (the deviation is detected). The waveform of the distance measurement value at the measured point of interest) is displayed on the display 12, and the display 12 and the sounding device display the notification information indicating that the breathing abnormality of the person P may have occurred. Output via one or both of 13.

In addition, in the monitoring processing unit 11, when both the increase / decrease time width and the decrease / increase time width are within the reference range at each attention measurement point, it is assumed that the person P is breathing normally. After making a determination, the display 12 displays the notification information indicating that fact.

Further, when the monitoring processing unit 11 cannot extract the measurement point of interest from the area on the bed B, for example, the breathing of the person P is stopped, or the person P is from the bed B. Since there is a possibility that the reflective portion 21 of the quilt C has been detached or the reflective portion 21 of the quilt C has been greatly displaced from the upper position of the chest Pa of the person P, the notification information indicating that fact is sent to the display 12 and the sounding device. Output via one or both of 13.

As described above, the monitoring device of the present embodiment can detect the movement (vibration) of the surface of the chest Pa accompanying the breathing of the person P. In this case, although the amount of displacement of the surface of the chest Pa is very small, by arranging the reflective portion 21 above the chest Pa, the amplitude of the distance measurement value at the measurement point of the chest Pa is large. Can be made to be significantly larger than the actual displacement of the chest Pa. As a result, the presence or absence of movement (vibration) of the surface of the chest Pa accompanying the respiration of the human P can be detected in a manner that is not easily affected by disturbance noise or the like (and thus with high reliability).

In the above embodiment, the embodiment in which the reflective portion 21 is attached to the quilt C (or the quilt C and the clothing worn by the person P on the upper body) has been described, but the quilt C or the person has been described. If the clothing worn by P on its upper body has a fabric portion having the same function as the reflective portion 21 preliminarily incorporated, it may be omitted to provide a reflective portion different from the comforter or clothing. It is possible.

Further, in the above embodiment, the embodiment in which the movement of the chest Pa accompanying the breathing of the sleeping person P has been described, but for example, even when the person is sitting or standing, the person can breathe. It is also possible to detect the accompanying movement of the chest Pa.

Further, the monitoring device of the present invention can detect not only the movement of the chest Pa accompanying the breathing of the human P but also the movement of the body surface portion accompanying the breathing of another animal, or any device. It is also possible to detect minute movements on the surface.

2 ... light emitting unit (transmitting unit), 3 ... light receiving unit (receiving unit), 4 ... measuring processing unit (distance measuring unit), 11 ... monitoring processing unit (motion detection unit), 21 ... reflecting unit (reflecting object).

Claims (3)

The transmission unit that transmits the measurement signal to the area where the monitored object exists, the reception unit that receives the reflection signal of the measurement signal transmitted from the transmission unit, and the transmitted measurement signal and the received reflection signal. Based on this, it is a monitoring device including a distance measuring unit that measures a distance to a measurement point set in the area.
At the measurement point, the measured value of the distance at the measurement point by the distance measuring unit changes according to a predetermined movement of the monitored object in the region, and the measured value of the distance is changed in the process of the change. Changes to a value larger than a predetermined amount by a predetermined amount or more than the actual distance, or the amount of change in the measured value of the distance in the process of the change is the actual distance according to the predetermined movement of the monitored object. It is a measurement point set so that the amount of change is larger than the specified amount of change.
A monitoring device including a motion detection unit that detects the occurrence of a predetermined motion of the object to be monitored based on a change in a measured value of a distance at the measurement point. In the monitoring device according to claim 1,
The monitoring device is characterized in that the object to be monitored is a person's chest, and the predetermined movement is vibration of the person's chest accompanying the person's breathing. In the monitoring device according to claim 1 or 2.
The posture of the monitored object with respect to the transmitting unit changes with the predetermined movement of the monitored object on the surface portion of the monitored object or an object in contact with the surface portion in the local region including the measurement point. Further provided is an attached reflecting object of the measurement signal, which is less likely to cause diffuse reflection of the measurement signal than the surface portion of the monitored object or an object in contact with the surface portion around the local region. A monitoring device characterized by.

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